Used for: giving clay a smooth finish, removing flaws

Polymer clay should be sanded underwater to avoid scattering dust. For this sanding, you will need wet/dry sandpaper; this usually is black and can be found in any hardware store.

Suitable grits for polymer clay start at 400 and go up from there. Many hardware stores only carry wet/dry sandpaper up to 600; some auto-parts stores carry finer sandpaper grits, up to 2000.

Buffer

Used for: creating a shiny, glossy finish

You can find a variety of electric buffers at your local hardware store. You can also try using a bench grinder (although some clayworkers have found them too hard on the clay) or handheld Dremel tool (best for smaller pieces such as beads).

To buff polymer clay, use a muslin or cloth wheel. Don't use polishing compounds (which will scratch the clay) or felt buffing wheels. While buffing, use a gentle circular motion. Avoid pressing the clay into the buffer, which will create gouges. The heat from the friction of the buffer can soften the clay enough that your fingerprints may appear on it, so keep the clay moving and avoid buffing any one spot long enough to heat it to that point.

Steel Wool

Used for: shining fired clay, rubbing a patina

This steel wool is not the coarse kind you use in the kitchen, but fine steel wool of the sort used by woodworkers to make a smooth finish after sanding or varnishing. It's available at hardware stores. Either steel or synthetic wool can be used; look for grades 0 (coarse) through 0000 (finest).

Needle file

Used for: enlarging and smoothing holes in beads

Needle files can also be found at hardware stores. Look for the round (cylindrical) type, and if possible, get a variety of sizes. Don't push the file too hard when reaming, or you may split the bead.

Adhesives

Used for: attaching clay pieces to other clay pieces, jewelry findings, or veneered objects

E6000 cement and gel cyanoacrylate adhesive (Superglue, Krazy Glue, Zap-A-Gap) seem to work well with polymer clay. Look for a gel-type, thick formula - the thick adhesive bridges gaps better than thin glue.

To attach clay to an object such as a box, try brushing a thin layer of ordinary white glue or Sobo glue onto the object, letting it dry to tackiness, then applying the clay. The layer of sticky glue helps the clay adhere better.

You can use polymer clay without any special finishing treatment at all. The finish of polymer clay right after firing varies by brand - Fimo has a slight gloss, Sculpey has a matte finish, Cernit is slightly waxy-looking. For many pieces, you may find that the clay's natural finish best enhances the effect you want. For other pieces, you may prefer the shinier or glossier finish available with various finishing techniques such as wet-sanding, buffing, and glazing. Buffing produces a deeper, more subtle sheen; glazing produces a harder shine and takes considerably less time.

How do I sand my clay to a shiny finish?

Sanding polymer clay is best done under water - either under the tap or in a basin. Use wet/dry sandpaper, starting with a grit of about 400 and progressing to at least 600. Sand each surface a few strokes with each grit of paper. When done, wipe off the piece and let it dry.

You can buff by hand with a clean soft cloth (terrycloth, t-shirt, or the pique knit used for polo shirts) by vigorously rubbing the piece for several minutes to bring out the shine. You can also use an electric buffer with a cloth or muslin wheel. If you use a power buffer, be sure to keep the clay moving while you buff, and hold it lightly against the wheel; pressing can cause gouges in the clay. (You can buff polymer clay without sanding it smooth first, but the shine you obtain will not be as great.)

For an alternative to heavy buffing use the fine steel wool made for wood finishing. Lightly rub the sanded clay with the steel wool, then hand-buff briefly, to bring out a bit of subtle shine.

Can I polish polymer clay in a rock tumbler?

Elise Winters has experimented with various techniques for polishing polymer clay in a tumbler. Her original article in the April/May 1996 issue of Lapidary Journal described using small bits of wet/dry sandpaper along with the beads to be polished; the sandpaper bits take the place of the grit normally used in a tumbler.

Later, she found a special polishing paper that gives superior results and can be used either in bits like sandpaper (for irregular pieces) or to line the inner surface of the tumbler (for beads). An article in the March/April 1997 issue of Jewelry Crafts describes this method. If you'd like to try this method, the special papers are available from Rio Grande, on page 374 A of their 2001 Tools & Equipment catalog (3M Tri-M-Ite Polishing Paper).

Several manufacturers of polymer clays also make gloss and matte glazes. These are brush-on finishes that dry in about an hour. Some glazes are water-based; try to avoid these, since they have a tendency to peel over time, particularly in jewelry or other pieces that have to withstand a lot of friction.

Another glaze that can be used is Future floor polish. This is actually an acrylic coating that works well on polymer clay. It is very thin, so to get the best shine, you need to sand and buff your pieces smooth before using it. When used on unsanded clay, it produces a finish more like matte glaze. You can also dip pieces in Future for a heavily-coated, very shiny look. (Be careful to rotate the piece back and forth a few times after dipping to get rid of the excess.)

Many clay artists have also successfully used Flecto Varathane Elite Diamond Finish. This is a lacquer found in hardware stores, in the area with the wood stains and finishes. It comes in satin (matte), semi-gloss, and gloss finishes. A piece with Flecto on it can be re-fired for a stronger glaze. Flecto will also bend and flex without peeling - an important consideration if you're using a flexible clay in thin sheets.

Both Flecto and Future are much less expensive in quantity than the polymer-clay manufacturers' glazes. Since they come in large containers, you may want to put some into a smaller container for your workspace to make it more manageable.

Do not use nail polish to lacquer your clay, and be careful about using other glazes. Many lacquers - including most nail polish - will react with the clay over time, causing it to turn sticky. Some glazes, especially spray-ons, never dry properly when used on polymer clay. If you want to try a new glaze, make sure to test it first.

How do I get a natural-looking, matte finish?

Polymer clay as it comes out of the oven has an attractive matte finish. If you want a little more shine, but still a subtle effect, you can rub the piece lightly with fine steel wool, then buff it with a cloth to bring out a bit of shine. Some of the clay manufacturers also make matte glazes, which are less shiny than the gloss types, but bring out the colors of the clay a bit.

How do I get rid of fingerprints or flaws in my finished clay?

You can sand away small flaws in your finished pieces with 320 or 400 grit sandpaper. Make sure not to press too hard, and check your piece frequently, to avoid sanding through a veneer or creating a flat spot. When you're through, you can restore the sheen of the sanded area by sanding it gently with a finer grit of paper, then lightly buffing the piece all over or using a matte glaze.

Why did my clay get sticky after I glazed it?

Some glazes react badly with the polymer clay. Either they never completely dry, leaving a sticky surface that attracts dust and lint, or they seem to dry but get soft and sticky months or years later. You can avoid this problem by sticking with the glazes made by the polymer clay manufacturers, or other glazes that you've experimented with and know to work with clay. (Remember when experimenting that problem glazes sometimes seem fine for months before they start reacting with the clay.)

Once this has happened to a piece, not much can be done to salvage it. You can try placing the piece in a low oven (200-250? Fahrenheit) for an hour or so; this sometimes sets a gummy glaze.

Polymer clay, being non-volatile, can be stored for months or years. Exposure to air will not hurt it, although it's best to keep it wrapped for protection from dust and lint. Unlike true earth clay, polymer clay does not contain water that can evaporate. The main danger to polymer clay is from excessive heat or ultraviolet light; these can partially fire the clay, making it unusable. Over time, the plasticizer that keeps the clay soft can also leach out, leaving hard, crumbly clay.

A common rule of thumb is that clay can be kept at least a year, sometimes for several years. Your clay will last longer if you keep it away from sunlight and heat.

How do I know whether a piece of clay has gotten too hard to work?

The rule of thumb here is that if you can still squidge the clay between your fingers - if it yields to pressure - then it can be worked. Borderline clay can often be rescued by adding softer clay or other substances to make it easier to condition.

If you're buying clay in a store and have the opportunity to test it, always check it for hardness, since occasionally clay is left in the sun on loading docks or otherwise mishandled in a way that causes it to harden prematurely. (Remember that some clay brands are harder than others and will normally yield only slightly to the pressure of your fingers.)

How long can I keep canes and finished pieces before firing them?

In general, you can keep a finished piece as long as you want before firing it. As always, make sure not to let dust get on the pieces, and make sure that unfired canes aren't stored touching each other or they will start to bond together and won't be separable without damage.

Do I need to recondition clay after it's been sitting around?

If you've conditioned a piece of clay and have then stored it for a while, you don't need to recondition it; it will retain the conditioned texture indefinitely. However, you may want to warm it before starting to work with it; warming makes the clay softer and easier to work with.

Since polymer clay is a plastic, it's very durable. The colors of polymer clay generally are stable in normal use, although a piece exposed to direct sunlight for years (such as a suncatcher or wind chime) will probably fade. There are artists who have pieces decades old that still look like new.

Thin pieces sometimes do break or chip. If your clay piece will be handled a lot or be in danger of bumps, and it will include protrusions or thin pieces, choose one of the stronger clay brands, and fire it for a longer time than usual for added strength.

How can I store polymer clay?

You don't need to store polymer clay in airtight containers, since it contains no water to evaporate. However, it should be wrapped or covered to prevent dust and lint from getting on it, and kept away from heat and sunlight.

Be careful about storing polymer clay in plastic containers or plastic wrap. Some types of plastic can be used with polymer clay, but others react with the plasticizer in the clay, and the clay eventually will begin to bond with the container. In particular, avoid putting polymer clay in polystyrene (recycling #6). Polyethyline (#2 or #4) and polystyrene (#5), however, seem to be compatible with polymer clay for storage.

For similar reasons, you shouldn't store different colors of clay without putting something between them, or store fired clay in contact with unfired clay. They'll eventually start to bond together.

You can wrap polymer clay in waxed paper before putting the clay into a storage box. The plasticizer does not react at all with waxed paper, although some plasticizer may leach into the paper over time. You can also store finished pieces (unfired) and unsliced canes this way.

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